THE SIGNIFICANCE OF LATENCY TIME IN ENZYME 

 DETERMINATION. 



By LOURENS G. M. BAAS-BECKING. 

 (From the Department of Botany, Stanford University, Pacific Grove.) 



(Received for publication, January 18, 1921.) 



Bredig and von Berneck,^ in their work on inorganic ferments, 

 determined the catalytic activity of platinum and manganese salts 

 on hydrogen peroxide by means of titration with potassium per- 

 manganate. In many of their experiments they found, however, 

 that the reaction velocity increased during the reaction. Bredig 

 and Marck^ attempt to explain this fact by a gradual activation of 

 the catalyzer by the substrate. Denham^ believes that the increase 

 in reaction velocity is due to absorption at the surface layer. The 

 results of Waentig and Steche^ on blood catalase seem to indicate 

 that the increase in reaction velocity is not a constant feature of the 

 catalase ; they found a constant, or even a decreasing, reaction velocity. 

 Senter,^ however, obtained opposite results with the same enzyme; 

 there were cases in which the velocity increased. It seems to me 

 that the controversy between different authors can, at least partially, 

 be solved by the following considerations. 



As I was able to demonstrate, the reaction does not start immedi- 

 ately after mixing the hydrogen peroxide with the enzyme solution. 

 For this experiment I used an autographic registration of catalase 

 action in a manometer. A certain latency period shows itself before 

 the reaction starts. Probably an adsorption compound is formed 

 during this latency period, which on decomposition liberates the 

 oxygen. In one case, I obtained a latency time of 98 seconds while 



^ Bredig, G., and von Berneck, R. M., Zt physikal. Chem., 1899, xxxi, 258. 

 ^ Bredig, G., and Marck, A., Gedenkboek aangeboden aan J. M. Van Bem- 

 melen, 1910, 342. 



3 Denham, G. H., Z. physikal. Chem., 1910, Ixxii, 686. 

 ^ Waentig, P., and Steche, O., Z. physiol. Chem., 1911, Ixxii, 256. 

 5 Senter, G., Z. physikal. Chem., 1903, xliv, 257. 



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